Conventionally, the general lighting device or lamp uses an incandescent light bulb, a light tube or a power-saving light bulb as a light-emitting element to provide illumination. With the advancement of science and technology, the design of the light-emitting diode (LED) as the light-emitting element is becoming more widespread and the light-emitting diode provides better lighting effects.
Nowadays, the awareness of environmental protection is gradually increased. It is an important issue to effectively utilize and develop resources with regenerative characteristics. As known, sunlight is an inexhaustible, inexhaustible, natural and clean source. For example, a solar panel is used to convert sunlight into electric energy, or the electric energy is further stored in a solar cell. That is, the solar panel and the solar cell can provide electric energy to associated devices. In addition, the lighting device or lamp using a motion sensing technology to control the on/off states of the light-emitting element is effective to achieve the power-saving benefit.
According to the motion sensing technology, a sensor is installed on a lighting device or lamp to sense the motion change of an object or the intensity change of the ambient light. Consequently, the on/off states of the light-emitting element are automatically controlled according to the change in the sensing area. The sensor for implementing the motion sensing technology includes a passive infrared sensor (PIR sensor) or a microwave sensor. For example, the associated technologies are disclosed in Chinese Patent Application No. 200520000991.X and 200810097926.1.
As the power-saving sensing applications become diversified, the space lighting devices or the security photography devices are operated according to the infrared (IR) sensing technology. Consequently, the manufacturers make efforts to increase the applications of the devices. For example, the lighting device with the automatic sensing function can be installed outdoors in combination with solar energy technology, so that the converted electric energy can be stored during daytime or sunny days. Alternatively, the lighting device is selectively installed indoors to use the utility power source or installed outdoors to use the solar energy. Alternatively, the lighting device is installed on an indoor wall in a wall-mounting manner or installed on the indoor ceiling in a suspension manner.
In case that the structure of the lighting device is specially designed, the lighting device can be used in different environments while increasing the diversity of the application and saving the development cost of different products. However, there are still some drawbacks. For example, the installation environment of the lighting device and the sensitivity condition (e.g., specified angle limitation or direction) of the infrared (IR) sensing technology influence the operating efficacy of the lighting device. In case that the installation position of the lighting device is changed from a wall to a ceiling and the sensing angle or direction is not accurately adjusted, the sensing area is improper and the function of automatically controlling the on/off states of the light-emitting element is adversely affected.
For solving the above drawbacks, many complicated rotation mechanisms are employed. By the rotation mechanisms, the sensing angle or direction of the overall sensing element, sensing mechanism or sensing module is correspondingly adjusted according to the installation position of the overall lighting device.
For solving the drawbacks of the conventional technologies, there is a need of providing an improved lighting device using a simpler technology.